This invention relates and is directed to a step useable in connection with construction walls of the type particularly encountered in manhole walls, masonry walls, retaining walls, and the like. These steps are typically received in holes formed in cast concrete or embedded in cast concrete or other like type walls, particularly in manholes.
In the constructions and applications for which this type of step is employed, the conditions to which the steps are exposed, unless the steps are of particular types and materials of construction, tend to cause them to deteriorate rapidly, with danger and hazards to the users of such steps and, further, requirements of replacement effort and expense. The steps are typically exposed directly to moisture and continued dampness for long periods of time, literally constantly and, further, to whatever chemicals may be present in the water, sewage and deleterious fumes emanating therefrom. Rapid corrosion, pitting and deteriorating of conventional metal steps from such various causes are well known. It is thus a principle object in a plastic step (plastic coated, steel reinforced step) to remain intact, impervious to the environment, strong and working for long periods of time under extremely adverse conditions.
Due to constant exposure of the outer surface of the step to dampness and moisture, as well as various adverse other materials, the steps may become slippery and/or coated, thereby providing a most precarious foothold for workmen. The provision of steps affording a sure foothold is necessary as two hundred plus pound men carrying heavy loads up and down the steps (of perhaps near equal weight) are not unusual.
Because plastic steps, even with the strong and durable plastics presently known to the art, per se, without a reinforcing metal bar therewithin, have not proved reliable, or strong enough in actual commercial use, plastic coated, steel core reinforced steps are one commercial product which is currently produced for use. The plastic provides a protective coating or shell against chemical action on the basic steel core frame and thus solves the problems of continuous presence of moisture and water, whether or not corrosive chemicals are present therein. The plastic also provides protection against electrical or electro-chemical action perhaps present in the environment if bare metal were present.
The particular improvement of the subject invention is directed to a new configuration of the drive-in or hammer-in ends of a plastic coated, steel reinforced manhole step. This particularly involves the outer configuration of the cast plastic sheath or coating on the outer three to four inches (typically) of the reinforcement bar of the manhole step type in question. Such new end piece configurations are improvements over (in both the herein disclosed forms thereof) the outer leg end configuration of the plastic step disclosed in the Peacock patent 4,100,997 and further over the same in the disclosure of Borst, Ser. No. 6,34,373, filed July 25, 1984 for "Drive-In Manhole Step Construction", now U.S. Pat. No. 4,610,330 issued Sept. 9, 1986.